Success of HPV Vaccination: 'Dramatic' Reduction in Cervical Cancer

Pam Harrison
November 04, 2021

New data from England show the success of the national program for vaccinating girls against human papillomavirus (HPV) to prevent cervical cancer.

Among young women who received the HPV vaccine when they were 12 or 13 years old (before their sexual debut), cervical cancer rates are 87% lower than among previous nonvaccinated generations.

"It's been incredible to see the impact of HPV vaccination, and now we can prove it prevented hundreds of women from developing cancer in England," senior author Peter Sasieni, MD, King's College London, London, United Kingdom, said in a statement. "To see the real-life impact of the vaccine has been truly rewarding," he added.

"This study provides the first direct evidence of the impact of the UK HPV vaccination campaign on cervical cancer incidence, showing a large reduction in cervical cancer rates in vaccinated cohorts," commented Kate Soldan, MD, UK Health Security Agency, London, in a statement.

Vanessa Saliba, MD, a consultant epidemiologist for the UK Health Security Agency, agreed, saying that "these remarkable findings confirm that the HPV vaccine saves lives by dramatically reducing cervical cancer rates among women.

"This reminds us that vaccines are one of the most important tools we have to help us live longer, healthier lives," she added.

The study was published online November 3 in The Lancet.

Approached for comment on the new study, Maurice Markman, MD, president, Medicine and Science Cancer Treatment Centers of America, noted that the results of the English study are very similar to those of a Swedish study of the quadrivalent vaccine alone.

"You can put any superlatives you want in here, but these are stunningly positive results," Markman told Medscape Medical News. He said that as an oncologist who has been treating cervical cancer for 40 years, particularly patients with advanced cervical cancer, "I can tell you this is one of the most devastating diseases to women, and the ability to eliminate this cancer with something as simple as a vaccine is the goal of cancer therapy, and it's been remarkably successful," Markman said.

"I can only emphasize the critical importance of all parents to see that their children who are eligible for the vaccine receive it. This is a cancer prevention strategy that is unbelievably, remarkably effective and safe," Markman added.

National Vaccination Program

The national HPV vaccination program in England began in 2008. Initially, the bivalent Cervarix vaccine against HPV 16 and 18 was used. HPV 16 and 18 are responsible for 70% to 80% of all cervical cancers in England, the researchers note in their article.

In 2012, the program switched to the quadrivalent HPV vaccine (Gardasil), which is effective against two additional HPV types, HPV 6 and 11. Those strains cause genital warts.

The prevention program originally recommended a three-dose regimen in which both HPV vaccines were used. Currently, two doses are given to girls younger than 15 years. In addition, a single dose of the HPV vaccine provides good protection against persistent infection. The efficacy rate of a single dose is similar to that of three doses, the authors comment.

Population-Based Registry

The new data come from a population-based cancer registry that shows the incidence of cervical cancer and noninvasive cervical carcinoma (CIN3) in England between January 2006 and June 2019.

The study included seven cohorts of women who were 20 to 64 years of age at the end of 2019. Three of these cohorts composed the vaccinated population.

The team reports that overall, from January 2006 through June 2019, there were 27,946 cases of cervical cancer and 318,058 cases of CIN3.

In the three vaccinated cohorts, there were around 450 fewer cases of cervical cancer and 17,200 fewer cases of CIN3 than would be expected in a nonvaccinated population.

The three vaccinated cohorts had been eligible to receive Cervarix when they were aged 12 to 13 years. A catch-up scheme aimed at 14- to 16-year-olds and 16- to 18-year-olds. Most of these persons were vaccinated through a school vaccination program.

The team analyzed the data for each of these cohorts.

Among the cohort eligible for vaccination at 12 to 13 years of age, 89% received at least one dose of the HPV vaccine; 85% received three shots and were fully vaccinated. Among these persons, the rate of cervical cancer was 87% lower than expected in a nonvaccinated population, and the rate of CIN3 was 97% lower than expected.

For the cohort that was eligible to be vaccinated between the ages of 14 and 16 years, the corresponding reductions were 62% for cervical cancer and 75% for CIN3.

For the cohort eligible for vaccination between the ages of 16 and 18 years (of whom 60% had received at least one dose and 45% were fully vaccinated), the corresponding reduction were 34% for cervical cancer and 39% for CIN3.

The authors acknowledge some limitations with the study, principally that cervical cancer is rare in young women, and these vaccinated populations are still young. The youngest would have been vaccinated at age 12 in 2008 and so would be only 23 years old in 2019, when the follow-up in this current study ended. The authors emphasize that because the vaccinated populations are still young, it is too early to assess the full impact of HPV vaccination on cervical cancer rates.

Editorial Commentary

"The relative reductions in cervical cancer, expected as a result of the HPV vaccination programme, support the anticipated vaccine effectiveness," comment two authors of an accompanying editorial, Maggie Cruickshank, MD, University of Aberdeen, Aberdeen, United Kingdom, and Mihaela Grigore, MD, University of Medicine and Pharmacy, Lasi, Romania.

"The scale of the HPV vaccination effect reported by this study should also stimulate vaccination programmes in low-income and middle-income countries where the problem of cervical cancer is a far greater public health issue than in those with well established systems of vaccination and screening," they comment.

"The most important issue, besides the availability of the vaccine ... is the education of the population to accept the vaccination because a high rate of immunization is a key element of success," they emphasize. "Even in a wealthy country, such as England with free access to HPV immunisation, uptake has not reached the 90% vaccination target of girls aged 15 years set by WHO [World Health Organization]."

The authors and editorialists have disclosed no relevant financial relationships. Markman is a regular contributor to Medscape Oncology. He has received income of $250 or more from Genentech, Inc, AstraZeneca Pharmaceuticals LP, Celgene, Clovis, and Amgen.

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Reviewed on 11/4/2021
References
SOURCE: Medscape, November 04, 2021. Lancet. Published online November 3, 2021.

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